I need to know if anyone has the flow numbers for the 6.0 heads, 317 casting, I seen them before and remember them being much better than LS1 heads and maybe even better than LS6 heads but have bigger combustion chambers but the rest of the specs are the same but bigger runners than LS1. If anyone has this info, it would help, I have the horrible 806 castings on my car so Im thinking if I mill the 6.0 heads enough I could gain good power.

So you plan on running 6.0L heads on a N/A 346? That's foolish. Those heads are meant for boost applications because of the larger chamber. Going with a big chamber head only to mill them a ton just to regain the compression that was lost is like spitting into the wind.

you should see some other guys setups runnng these heads milled, making alot of power and not on boost.

On a 3.89" bore? Links? The only difference between those heads and LS6 heads is the combustion chamber size. I guess I just don't see the point...

Besides, whatever flow numbers anyone posts up are JUNK. Those heads would be tested on a 4.030 or 4.060 in most cases. Not only would they flow significantly less on the LS1s bore, but milling them also affects flow.

they flow identical to LS6 heads on the same bore, why do I have to do what you want to do? If I decide to mill these heads and bolt them on, it would be my decission and milling them would make them the same as LS6 heads but at a cheaper cost for me. Ive seen these things on cars and seen what they can do. A guy down here in texas, 6.0 LQ9, Cam Only with these heads milled .030 made 470 to the wheels. The car was featured in magazines etc. Ill try to find the link to them. This is nothing new, alot of people have done this with these heads.

The purpose of this thread is to find out the flow numbers, found out they are identical to LS6 heads, not sure what either flow so really wanting to know. Heard LS6 flow 255/257 so if that information is wrong, id really like to know.

On a 3.89" bore? Those heads would be tested on a 4.030 or 4.060 in most cases. Not only would they flow significantly less on the LS1s bore, but milling them also affects flow.

Quote:

Originally Posted by Mike96z

A guy down here in texas, 6.0 LQ9, Cam Only with these heads milled .030 made 470 to the wheels. The car was featured in magazines etc. Ill try to find the link to them. This is nothing new, alot of people have done this with these heads.

You are aware that an LQ9 has a 4.00" bore, correct? Totally different ball game, and will affect flow numbers. But do what you want, obviously you didn't post this thread asking for help or other peoples experience and input.

Milling the head will lose flow b/c making the chamber smaller will shroud the valve more.

yea, i bet you have flow tested a milled set of 317 casting heads

not all heads are the same, i understand it was on a 4.000 bore, the flow numbers im refering to were on a 5.7 bore. And if the heads can hold up on a 470hp LQ9, there is absolutely no reason why they cant hold up on a cam only 5.7.

Either way, I may be going a different route, found a trade for some ported 853 casting LS1 heads.

not all heads are the same, i understand it was on a 4.000 bore, the flow numbers im refering to were on a 5.7 bore. And if the heads can hold up on a 470hp LQ9, there is absolutely no reason why they cant hold up on a cam only 5.7.

NOBODY TESTS OR USES THOSE HEADS ON A 3.89" BORE! YOU WILL NOT FIND FLOW NUMBERS FOR THOSE HEADS ON A 3.89" BORE.

When you put those 317s on, make sure you go with a 2" primary header, a 224 duration cam and a sheetmetal intake - it will run great.

well if you guys think you know it all. Would I get a better gain from a LS6 intake or ported 853 heads? and how hard is it to make a set of 853 heads flow like LS6 heads.

Knowledge comes from experience, actually doing the things you talk about, and not paying some shop to do it or reading about it online. You will get more from the ported heads, however without an intake to feed it you are still choking the motor. 853's can be ported to flow as well as stock LS6 heads, but the amount of money you will spend to get them ported you might as well just buy a better head to begin with.